Fabrication and Electrical Properties of Potassium Niobate Ferroelectric Ceramics

Potassium niobate, KNbO 3 (KN), ceramics were prepared by a modified conventional ceramic fabrication process to characterize their piezoelectric properties. The modified process involving two-stage calcination (first stage at 600 °C and second stage at 1000 °C) is very effective in obtaining KN ceramics with a high density ratio >96% and a high resistivity, ρ, of >10 12 Ω·cm and that are nondeliquescent. The KN ceramics showed good piezoelectric properties in terms of the electromechanical coupling factor, k 33 , the piezoelectric constant, d 33 , and the mechanical quality factor, Q m , which are 0.49, 91.7 pC/N, and 325, respectively. They were poled at a DC electric field of 5 kV/mm at 150 °C.